The Prebiotic and Techno-Functional Potential of Microbial Exopolysaccharides for Human Health and Food Systems

Microbial exopolysaccharides (EPS) represent a diverse class of biopolymers holding considerable promise as functional food ingredients. This review analyzes the dual function of microbial EPS as a candidate for prebiotic agents and techno-functional additives. Differentiating between broad chemical categories and validated functional ingredients is critical. Many EPS are resistant to digestion; however, only those that meet the criteria established by the International Scientific Association for Probiotics and Prebiotics (ISAPP)-notably, selective utilization by host microorganisms that confer health benefits-are classified as prebiotics. This review examines the "EPS-microbiota-host axis," demonstrating how specific prebiotic EPS influence gut ecology to produce short-chain fatty acids (SCFAs). These metabolites regulate immunomodulatory and systemic metabolic homeostasis, which may have therapeutic benefits for conditions including diabetes and obesity. It is essential to differentiate microbiota-mediated effects from direct biological mechanisms associated with "bioactive EPS," including immune receptor modulation, which operate independently of fermentation and should not be equated with postbiotics. Beyond health, the structural complexity underpinning these activities confers significant techno-functional utility. We explore EPS as natural emulsifiers, rheology modifiers, and biodegradable packaging materials, emphasizing their stabilizing roles in dairy and bakery systems. Finally, we examine techno-economic barriers, particularly production scalability, that hinder widespread adoption and discuss the potential of synthetic biology to engineer "designer" polysaccharides. This synthesis clarifies the precise roles of microbial EPS as sustainable, multifunctional ingredients in developing next-generation healthy foods.